The present invention relates to an improved dielectric barrier discharge (DBD) plasma actuator which can be used for drag reduction on wings, nacelles and/or fuselage of aerodynamic vehicles and devices, such as aircraft, cars, turbines, and the like.
DBD actuators are known and used to form a low-temperature plasma between a pair of asymmetric electrodes by application of a high-voltage AC signal across the electrodes. Consequently, air molecules from the air surrounding the electrodes are ionized, and are accelerated through the electric field.
As an example, aircraft may include surfaces that have regions where the airflow over the surface is not able to follow the contour of the surface. The airflow is said to “separate” from the surface in these regions. The separation of the airflow from the surface may result in increased fuel consumption, reductions and/or limitations on travel speed and/or range, and the carrying capacity of the aircraft. Previous attempts to prevent airflow separation included blowing and/or suctioning air from orifices in the surface located in or near the separated flow region. Slots were formed in the surface and jets of pulsating air were periodically discharged from the slots to prevent airflow separation. The jets were formed by voice coil based actuators or piezoelectric actuators provided in a linear array along the surface. The use of voice coil based actuators or piezoelectric actuators to prevent airflow separation required a change in the design of the surface to accommodate the actuators. The voice coil based actuators or piezoelectric actuators added weight and expense to the aircraft from the slot, actuators and wires.
DBD plasma actuators have been proposed for use in controlling flow of aircraft. For example, U.S. Pat. No. 7,624,941 to Patel et al, teaches a method of controlling aircraft, missiles, munitions, and ground vehicles with plasma actuators. U.S. Pat. No. 8,016,247 to Schwimley et al teaches a plasma flow control actuator system and method for directional and attitude control, which employs three electrodes. U.S. Pat. No. 8,308,112 to Wood et al teaches a plasma actuator for drag reduction by generating a plasma in air surrounding the surface at a position where the airflow would separate from the surface in the absence of the plasma.